WIP function to turn lager config into logger config

src/lager.erl

@@ -36,7 +36,8 @@
         get_loglevel/1, get_loglevel/2, set_loglevel/2, set_loglevel/3, set_loglevel/4, get_loglevels/1,
         update_loglevel_config/1, posix_error/1, set_loghwm/2, set_loghwm/3, set_loghwm/4,
         safe_format/3, safe_format_chop/3, unsafe_format/2, dispatch_log/5, dispatch_log/7, dispatch_log/9,
-        do_log/9, do_log/10, do_log_unsafe/10, pr/2, pr/3, pr_stacktrace/1, pr_stacktrace/2]).
+        do_log/9, do_log/10, do_log_unsafe/10, pr/2, pr/3, pr_stacktrace/1, pr_stacktrace/2,
+        configure_logger/0]).
 
 -type log_level() :: none | debug | info | notice | warning | error | critical | alert | emergency.
 -type log_level_number() :: 0..7.
@@ -689,6 +690,56 @@ rotate_handler(Handler) ->
 rotate_handler(Handler, Sink) ->
     gen_event:call(Sink, Handler, rotate, ?ROTATE_TIMEOUT).
 
+
+configure_logger() ->
+    Handlers = application:get_env(lager, handlers, lager_app:default_handlers()),
+    WhitelistedLoggerHandlers = application:get_env(lager, whitelisted_logger_handlers, []),
+    [ ok = logger:remove_handler(Id) || #{id := Id} <- logger:get_handler_config(), not lists:member(Id, WhitelistedLoggerHandlers) ],
+    add_logger_handlers(Handlers).
+
+add_logger_handlers([]) ->
+    ok;
+add_logger_handlers([{lager_console_backend, Config}|Tail]) ->
+    Level = proplists:get_value(level, Config, info),
+    Formatter = proplists:get_value(formatter, Config, lager_default_formatter),
+    FormatterConfig = proplists:get_value(formatter_config, Config, []),
+    logger:add_handler(console, logger_std_h, #{level => Level, formatter =>
+                                                {lager_logger_formatter, #{report_cb => fun lager_logger_formatter:report_cb/1,
+                                                                           formatter => Formatter,
+                                                                           formatter_config => FormatterConfig}}}),
+    PriConfig = #{level := CurrentLevel} = logger:get_primary_config(),
+    case lager_util:level_to_num(Level) > lager_util:level_to_num(CurrentLevel) of
+        true ->
+            logger:set_primary_config(maps:merge(PriConfig, #{level => Level}));
+        false ->
+            ok
+    end,
+    add_logger_handlers(Tail);
+add_logger_handlers([{lager_file_backend, Config}|Tail]) ->
+    Level = proplists:get_value(level, Config, info),
+    File = proplists:get_value(file, Config),
+    Size = proplists:get_value(size, Config),
+    Count = proplists:get_value(count, Config),
+    Formatter = proplists:get_value(formatter, Config, lager_default_formatter),
+    FormatterConfig = proplists:get_value(formatter_config, Config, []),
+    logger:add_handler(list_to_atom(File), logger_disk_log_h, #{level => Level,
+                                                     file => File,
+                                                     max_no_files => Count,
+                                                     max_no_bytes => Size,
+                                                     formatter =>
+                                                     {lager_logger_formatter, #{report_cb => fun lager_logger_formatter:report_cb/1,
+                                                                                formatter => Formatter,
+                                                                                formatter_config => FormatterConfig}}}),
+    PriConfig = #{level := CurrentLevel} = logger:get_primary_config(),
+    case lager_util:level_to_num(Level) > lager_util:level_to_num(CurrentLevel) of
+        true ->
+            logger:set_primary_config(maps:merge(PriConfig, #{level => Level}));
+        false ->
+            ok
+    end,
+    add_logger_handlers(Tail).
+
+
 %% @private
 trace_func(#trace_func_state_v1{pid=Pid, level=Level, format_string=Fmt}=FuncState, Event, ProcState) ->
     lager:log(Level, Pid, Fmt, [Event, ProcState]),

src/lager_app.erl

@@ -31,7 +31,8 @@
          start_handler/3,
          configure_sink/2,
          stop/1,
-         boot/1]).
+         boot/1,
+         default_handlers/0]).
 
 %% The `application:get_env/3` compatibility wrapper was useful
 %% for other modules in r15 and before
@@ -281,6 +282,9 @@ stop(Handlers) ->
           error_logger:add_report_handler(Handler)
       end, Handlers).
 
+default_handlers() ->
+    ?DEFAULT_HANDLER_CONF.
+
 expand_handlers([]) ->
     [];
 expand_handlers([{lager_file_backend, [{Key, _Value}|_]=Config}|T]) when is_atom(Key) ->